If the VswitchID is specified for a scaling group, you cannot attach Classic ECS instances or ECS instances on other VPCs to the scaling group.

If the VswitchID is not specified for the scaling group, ECS instances of the VPC type cannot be attached to the scaling group.

The interface can be called only when the scaling group is active.

The interface can be called only when the scaling group has no scaling activity in progress.

When the scaling group has no scaling activity in progress, the interface can be directly executed without cooldown.

Successfully calling this interface only means that the Auto Scaling service has accepted the call request, and the scaling activity can be executed, but does not necessarily mean that the scaling activity can be successfully executed. You can use the returned ScalingActivityId to check the status of the scaling activity.

The call attempt may fail when the total capacity of instances specified by this interface plus the instances of the scaling group is greater than MaxSize.

The manually attached ECS instance is not associated with the active scaling configurations of the scaling group.